Here’s a report about Rio Grande River administration from Julián Aguilar writing for The New York Times. Click through and read the whole article. Here’s an excerpt:

Researchers say the Rio Grande is one of the most studied and controversial bodies of water in North America. But with various levels of government in two countries making decisions that influence it, the Rio Grande has become the subject of interstate and international legal battles that have intensified during the continuing drought.

“It’s obvious there isn’t anything like” the Rio Grande, said Gabriel Eckstein, a professor at the Texas A&M University School of Law and the director of the International Water Law Project. “It’s a border river amongst U.S. states and internationally. You just have so many stakeholders with different jurisdictions and laws that apply.”[…]

It is at the New Mexico border where water needs and individual interpretations of laws create one controversy. New Mexico and Texas are embroiled in a lawsuit over groundwater extraction. Texas argues its neighbor is allowing excessive pumping, reducing the flow of the Rio Grande into Texas.

A 1938 compact between Colorado, New Mexico and Texas governs how much of the river’s water the states are allotted. Mr. Eckstein says that the compact does not consider different state practices.

“Are they allowed to do it? That’s a different question,” he said. “New Mexico has a different law for groundwater versus surface water, and it’s unclear whether the compact relates to that.”

As the Rio Grande continues southeast, intrastate needs create more domestic discord. Tom Miller, the director of the Lamar Bruni Vergara Environmental Science Center in Laredo, said people there are monitoring a proposal by the city of San Antonio that would pipe in water from the San Felipe Springs in Val Verde County. The springs feed the river, and Mr. Miller said the action would harm one of the few hundred springs left in a state that once had thousands.

“We’re very concerned about this intrabasin transfer of water,” said Mr. Miller, whose Webb County office is just feet from the Rio Grande’s banks. “How will it affect the general water table of the river, and will it lower so that the water will have a harder time being delivered to the intended recipients? How will it affect ours?” San Antonio officials say considering the option is necessary to help satisfy its growth needs, which have been magnified by the drought.

The clearest example of how international politics affects the Rio Grande is a 1944 water treaty between the United States and Mexico. The treaty states that Mexico must provide the United States surface water from Mexican tributaries that feed into the river. In turn, the United States is to deliver water from the Colorado River. Mexico is supposed to provide 1.75 million acre-feet of water every five years. American officials contend that Mexico should supply 350,000 acre-feet annually, unless prevented by extreme environmental circumstances. Others say Mexico can make good on its delivery at any point during the cycle.

Sally Spener, a foreign affairs specialist with the El Paso-based International Boundary and Water Commission, said that as of Nov. 23, the supply deficit was 275,000 acre-feet, down from 484,000 in June.

The deficit prompted Senators John Cornyn and Ted Cruz, Republicans of Texas, to file legislation urging Mexico to comply and Gov. Rick Perry to write the Obama administration with a similar demand.

But Mexico has not technically violated the treaty. And in certain areas along the Rio Grande, its tributaries are the main supplier of water. Mexico also cites the drought as one reason it continues to hold on to its supply.

At Falcon Lake, a massive reservoir that straddles Mexico at Tamaulipas State and Webb and Zapata Counties in Texas, more than 80 percent of the water that is distributed comes from Mexico, Mr. Miller said…

Mr. Eckstein said that bureaucratic hurdles also affect what stakeholders know about the river and how it is fed. Transnational aquifers, he said, are a mystery because data is not shared across the border. Knowing how many aquifers span the border would inform public use practices and legislation, he said, citing the basics of the hydrological model.